R1-2601785
discussion
Discussion on 6G WUS Operation in RRC States
From FUTUREWEI
FUTUREWEI's prior position on
10.6.1.2
at
RAN1#124
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Proposes a unified 6G DL WUS of OFDM-based sequence design that claims functionality from both Rel-17 PEI and Rel-19 LP-WUS for RRC IDLE/INACTIVE operation, using codepoint-based indication with at least an all-subgroups codepoint and supporting a maximum of at least 31 subgroups per PO with association to at least 4 POs. Argues that 6G UE EE processing power state assumptions—specifically no NF degradation relative to the main radio and relative power within Rel-18/19 LP-WUR ON range—eliminate the need for Rel-19's conditional entry/exit condition based on serving cell measurements and enable PDCCH as the coverage target for energy saving. For RRC CONNECTED operation, proposes starting from Rel-19 Option 1-2 monitoring to decouple measurement requirements from PDCCH monitoring, while requiring SCell dormancy indication capability and increased wake-up capacity beyond Rel-19 LP-WUS to fully claim Rel-16 DCP functionality.
Summary
This Futurewei contribution discusses the design of 6G Downlink Wake-Up Signal (WUS) based on OFDM sequences, analyzing coverage, RRC IDLE/INACTIVE, and RRC CONNECTED operations based on Rel-19 LP-WUS. The document presents 15 observations and 4 proposals aimed at unifying paging indication and energy-saving notification functionalities in 6G.
Position
Futurewei proposes a unified 6G DL WUS design based on OFDM sequences to replace both Rel-17 PEI and Rel-19 LP-WUS for idle/inactive paging, and both Rel-16 DCP and Rel-19 LP-WUS for connected state energy saving — avoiding multiple options for the same functionality. They propose extending coverage target to Broadcast PDCCH based on the 6G 'EE processing' power state, which has no NF degradation and falls within Rel-18/19 LP-WUR ON-state relative power, thereby eliminating the Rel-19 LP-WUS conditional entry/exit condition based on serving cell measurements. They propose adopting Rel-19 LP-WUS codepoint-based wake-up indication (including an all-subgroups codepoint), supporting at least 31 subgroups per PO associated with up to 4 POs. They further propose using DL WUS to dynamically indicate paging occasion distribution patterns (sparse, densely clustered, or grouped) and to support SCell dormancy indication with increased capacity compared to Rel-19's 32-codepoint limit. They target coupling serving cell measurement with DL-WUS monitoring in the EE processing state and recommend sequence design with good time domain or dual time/frequency domain characteristics for the primary synchronization signal to reduce measurement complexity.
Key proposals
- Proposal 1 (Sec 3.2): Consider DL WUS of OFDM based sequence for a unified early paging indication functionality in 6G using codepoints with at least an all subgroups indication codepoint, while supporting a maximum of at least 31 subgroups per PO and association to a maximum of at least 4 POs.
- Proposal 2 (Sec 3.2): Consider the use of DL WUS of OFDM based sequence to indicate paging occasions/frames sparse distribution, densely clustered distribution, and/or grouping configuration.
- Proposal 3 (Sec 3.2): At least serving cell measurement based on EE processing together with DL-WUS monitoring should be a target design.
- Proposal 4 (Sec 3.3): Consider how to support dormancy indication using DL WUS of OFDM based sequence with an increased wake-up indication capacity, compared to Rel-19 LP-WUS design, for a unified energy saving information notification functionality in RRC Connected state of 6G.